Distal humerus fracture

Definition

Also named supracondylar fracture, a distal humeral fracture is a type of elbow fracture involving the lower (distal) part of the arm bone. At the elbow the humerus connects with the ulna and allows the rotation of the ulna when the hand is moved palm up or palm down. A distal humerus fracture can impair or block completely the movements of the elbow.

Pathology

The fracture of the distal humerus comprises 2% of all adult fractures but is very common in children (up to 60%). It is found either as an isolated fracture or in conjunction with other fractures of the arm and elbow joint. It is generally defined as an extension or flexion fracture. Injuries associated with a distal humerus fracture are:

Elbow dislocation

Vascular damage (brachial artery tear or compression)

Compartment syndrome of the arm and necrosis of soft tissue due poor blood supply

Injuries to the radial nerve, causing temporary/permanent flexion of the wrist (drop hand)

Classification

In adults, the classification of distal humerus fractures refers to the mechanisms of injury:

Extension-type (98%): the distal fragment is displaced towards the back (posteriorly)

Flexion-type (uncommon): the distal fragment is displaced to the front (anteriorly)

In children, the Gartland classification for extension type of distal humerus fractures corresponds to the Arbeitsgemeinschaft Osteosynthese (AO) Mùˆller classification for adults as mentioned below in the parentheses.

Type I (extra-articular fracture): undisplaced fractures with unaltered bone alignment

Type II (partial articular fracture): posterior displacement fracture retaining the integrity of the posterior segment of the bone

Type III (complete articular fracture): complete displacement of the distal fragment posteriorly.

Causes

Distal humeral fractures are caused by direct trauma to the arm or elbow and by axial loading transmitted through the elbow. Most common causes are:

Traumatic event (eg. motor vehicle, bicycle accidents)

Fall with the outstretched arm where the ulna pushes towards the humerus

Fall on the flexed elbow

Direct impact with a hard object (hockey/baseball bat, car parts during a collision)

Pathological fractures due to osteoporosis or cancerous metastatic growth.

Risk factors

The most frequent risk factors leading to a distal humerus fracture include:

Tendency to fall in elderly individuals (poor vision, lack of physical exercise)

Medical conditions (diabetes, seizure)

Sports (bicycle, horse riding)

Contact sports (football, rugby)

Post-menopausal age in women

Cancerous metastases

Symptoms

The most common symptoms of a distal humerus fracture are:

Severe acute pain at time of accident

Pain at touch

Swelling

Bruising

Obvious deformity of the distal arm

Inability to move the elbow

Bone exiting the skin in open fractures

Diagnosis

The physical examination begins with the medical history including the causes leading to the distal humerus fracture. The examiner will look for the presence of bruises of the distal arm as a sign of possible humerus fracture. Additional evaluation includes:

Changes in the elbow contour

Restrictions in the range of movement of the elbow, fingers and wrist

Test for nerve damage (sensation at touch, muscle weakness, nerve palsy)

Monitoring of radial and ulnar artery pulses to assess vascular integrity

X-rays are the first approach to detect a distal humerus fractures and assess its classification. A CT scan may be performed if necessary to explore further the type of fracture.

Assessment of the radial nerve

The radial nerve innervates the dorsal extrinsic muscles in the forearm. Injury of this nerve may ca0use hand drop. Functional tests of the radial nerve:

Extension of the wrist and metacarpo-phalangeal (MCP) joints with abduction and extension of the thumb

On examination, the fingers are in flexion at the MCP joints and the thumb are adducted

Dysesthesia or anaesthesia on the dorsum of the thumb

Rarely, the median or ulnar nerves are affected in parallel to injuries to the radial nerve.

Treatment

Nonoperative treatment

In case of undisplaced or minimally displaced distal humeral fractures conservative treatment forms a standard management. A splint or sling is applied and frequent X-rays taken to monitor the progress of fracture healing. During the initial period after injury the elbow is immobilised, after which a gentle physiotherapy can begin.Additional treatments include:

Ice pads

Administration of NSAIDs

Pain killers

Complications

With either conservative or surgical treatment, complications after distal humerus fracture can occur:

Non-union of the fracture (when the gap between the bone extremities is not closed)

Mal-union when the fracture heals with abnormal bone alignment

Infection

Post-surgery pain

Temporary damage to the radial nerve

Vascular damage

Joint stiffness of the shoulder and elbow

Ossification of soft tissues or heterotopic ossification in adjacent muscles, tendons

Second surgery in case of non union and removal of metal

Rehabilitation

Initially, after either conservative or surgical treatment a cast or splint is applied in most patients with distal humerus fracture. Physical therapy can commence as soon as the fracture is considered to be stable to prevent elbow stiffness, which may occur after prolonged immobilisation. NSAIDs and pain medications can aid the convalescence by reducing inflammation, swelling and pain. Recovery after distal humerus fracture can be a lengthy process (6 months) and the patient may never be able to lift weights or straighten the arm in full. Patients often display an extension deficit of up to 25 degree without any major functional impairment due to compensation of other joints of the affected arm, i.e. shoulder and wrist joint. Standard rehabilitative therapy also includes:

Massage

Dry needling

Joint mobilisation

Stretches

Electrotherapy

Activity modification advice

Return to sport/work plan

Postural taping

Prevention

The main preventative measure aims at reducing the risk of falls in the elderly and protect the arm if collisions occur during sport or biking/motor biking in younger individuals. Other preventive strategies are:

Elbow bracing when returning to sport

Postural taping

Osteoporosis treatment

Use of devices to improve elderly stability and avoid falls

Modification of physical activities

Physical exercise to improve muscle strength, flexibility and posture